Find the least value that must be given to number a so that the number 91876a2 is divisible by 8.
Solution:
If a number is divisible by 8 then its last three digits have to be divisible by 8
The number 91876a2 has 6a2 as its last three digits.
Therefore 6a2 has to be divisible by 8
Therefore a = 3 or 7
The lower of the two values is 3.
Therefore the least value of ‘a’ which will make 6a2 divisible by 8 is 3.
✦ Try This: Find the least value that must be given to number a so that the number 91876a2 is divisible by 11.
For a number to be divisible 11 the difference of the sum of digits in the odd places and sum of digits in even places is either zero or divisible by 11.
So if the given number is 91876a2 then,
9 + 8 + 6 + 2 = 1 + 7 + a
a = 22 - 8 = 14
But ‘a’ is a single digit number.
Therefore using the other criterion we have
(9 + 8 + 6 + 2) - (1 + 7 + a ) = 11
a = 9 + 8 + 6 + 2 - 1 - 7 - 11 = 6
a = 6
The least value of ‘a’ for the number to be divisible by 11 is 6.
☛ Also Check: NCERT Solutions for Class 8 Maths Chapter 16
NCERT Exemplar Class 8 Maths Chapter 13 Problem 45
Find the least value that must be given to number a so that the number 91876a2 is divisible by 8.
Summary:
The least value that must be given to number a so that the number 91876a2 is divisible by 8 is 3
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